Watch: Did Venus Williams reveal gender of Serena's baby?

Venus Williams may have let it slip Wednesday that sister Serena is expecting a baby girl.

While being interviewed following her second-round win over Japan's Kurumi Nara at the French Open on Wednesday, Venus was asked if she's given any thought to what Serena's unborn child is going to call her.

"She's going to call me 'Favorite Aunt,'" Venus said.

Serena recently told Vogue's Andre Leon Talley that she and fiance Alexis Ohanian were keeping their baby's gender a surprise.